Modern pollen-vegetation relationships along altitudinal vegetation belts in the Leigong Mountain of southwestern China

Understanding the distribution, dispersal, and correlation of modern pollen with vegetation in mountainous regions is essential for establishing accurate modern analogs for fossil pollen records. This study, conducted in Leigong Mountain on the Yunnan-Guizhou Plateau of southwestern China, involved the collection of 35 surface soil samples from diverse vegetation communities along an elevational gradient ranging from 1210 to 1875 meters. The results reveal a close correspondence between modern pollen assemblages and vegetation zones. Principal Component Analysis (PCA) results indicate that pollen assemblages can effectively distinguish between subtropical montane evergreen broad-leaved forest (SEBF) and subtropical montane deciduous broad-leaved forest (SDBF). However, both SEBF and SDBF show significant overlap with subtropical montane evergreen-deciduous broad-leaved mixed forest (SEMF). Detrended Correspondence Analysis (DCA) results clearly distinguish the three vegetation zones, and the first axis of DCA shows a significant positive correlation with elevation (p < 0.01, R=0.48). Discriminant Analysis (DA) successfully assigns 94.4% of the modern pollen samples to their respective vegetation zones. Pollen taxa such as Impatiens, Aster-type, and Rosaceae exhibit significant indicative capabilities for the SEBF zone, effectively distinguishing this vegetation zone from others. Pinus and Alnus display overrepresentation in the Leigong Mountain region, while Quercus (D, deciduous-type) and Poaceae exhibit high representation in the SEBF zone. In the SEBF zone, both pollen diversity and richness are the lowest. Our study reveals the complex relationship between the richness and diversity of pollen and vegetation. The diversity and richness of tree and shrub pollen are found to be lower than those of the corresponding plants. The pollen-vegetation relationship elucidated in this study serves as a critical reference for reconstructing ancient environments from fossil pollen retrieved in this region.